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How FPGAs work, and why people will buy them (2013)

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Re: How FPGAs work, and why people will buy them (2013)

#41

Post by Rebelgecko »

LeifCarrotson wrote: post #32
monocasa wrote: post #3

Earlier quoted context omitted.

And to be fair, since then FPGAs have exploded in non ASIC prototyping use cases. They're even starting to be used for some consumer electronics.

I'm interested in seeing some examples of their use in consumer electronics. I think this article would be a lot more compelling if it had a section on "You've already bought one if you have a (hypothetically) Roomba vaccum/ Tesla Model S/ Thinkpad laptop/ Ubiquiti router." I'm pretty sure most of those don't have FPGAs, but would be curious to see a list of things which do. I am by no means a representative consumer…

I think they're more common than you think

The Model S has at least one FPGA, as do some of Ubiquiti's products. I don't know about the Thinkpad, but Apple has used cheap Lattice FPGAs for interfacing between different hardware components. Macbook Pros have used them in the past (IIRC for driving the display and interfacing with the battery), as have iPhones.

Re: How FPGAs work, and why people will buy them (2013)

#42

Post by TomVDB »

nraynaud wrote: post #39
TomVDB wrote: post #34

Earlier quoted context omitted.

Whenever people ask this question, I'm the broken record with the same reply: start out with the cheapest kit possible, an Altera EP2C5TQ144 development board. http://land-boards.com/blwiki/index.php?title=Cyclone_II_EP2... They are old, and you need a slightly older version of the Altera Quartus software suite, but they are dirt cheap. Go to eBay, search for EP2C5TQ144, and you can find development kits including pr…

I'd advise people to start with a Cypress PSoC MCU, they have the taste of FPGA, but have a lot of useful stuff for various projects, and I bought 10 MCUs for $10.

I just googled it and they seem to be MCUs with no programmable logic?

What feature gives them a taste of an FPGA?

Re: How FPGAs work, and why people will buy them (2013)

#43

Post by atq2119 »

TomVDB wrote: post #38
davemp wrote: post #5

> FPGAs are a programmable platform, but one designed by EEs for EEs rather than for programmers. This is the problem with FPGAs. Their performance and utility is not really disputed. Working with them is so un-ergonomic that it's frankly embarrassing. The EE world is notoriously closed/proprietary making it incredibly difficult to explore novelty or customize tooling to suit specific needs. The situation is reminisc…

> The EE world is notoriously closed/proprietary making it incredibly difficult to explore novelty or customize tooling to suit specific needs. The EE world could use novelty tooling to increase the efficiency by which you create RTL. But that can easily be done today if you consider Verilog to be an intermediate representation. So I think you're talking about the tooling on the steps to go from RTL to bitstream? Wha…

There's potentially tremendous value in having an open bitstream.

To get the most out of hardware, you need feedback on how many LUTs each part of your design uses, where the critical dependencies are for the achievable clock rates, and so on.

It's difficult to get this information in a usable way in practice today even when you're writing Verilog. Using Verilog as an intermediate language makes the problem significantly worse.

Imagine there was the equivalent of LLVM for FPGA development. Without open bitstreams, that's never going to happen. (Even with open bitstreams, it'd need tremendous effort to get there, but at least there'd be a chance.)

Re: How FPGAs work, and why people will buy them (2013)

#44

Post by snaky »

TomVDB wrote: post #42
nraynaud wrote: post #39

Earlier quoted context omitted.

I'd advise people to start with a Cypress PSoC MCU, they have the taste of FPGA, but have a lot of useful stuff for various projects, and I bought 10 MCUs for $10.

I just googled it and they seem to be MCUs with no programmable logic? What feature gives them a taste of an FPGA?

Cypress call it 'UDB'.

https://www.eevblog.com/forum/projects/no-bitbanging-necessa...

Re: How FPGAs work, and why people will buy them (2013)

#45

Post by mastercheif »

LeifCarrotson wrote: post #32
monocasa wrote: post #3

Earlier quoted context omitted.

And to be fair, since then FPGAs have exploded in non ASIC prototyping use cases. They're even starting to be used for some consumer electronics.

I'm interested in seeing some examples of their use in consumer electronics. I think this article would be a lot more compelling if it had a section on "You've already bought one if you have a (hypothetically) Roomba vaccum/ Tesla Model S/ Thinkpad laptop/ Ubiquiti router." I'm pretty sure most of those don't have FPGAs, but would be curious to see a list of things which do. I am by no means a representative consumer…

FPGAs are starting to see extensive use in the high end audio market for implementing custom filtering, DSP, and discrete DAC mapping algorithms.

Here's an interview with Rob Watts, a DAC designer who's getting the best measurements in the industry right now with his Chord DAC's (specifically Chord DAVE) http://www.the-ear.net/how-to/rob-watts-chord-mojo-tech

Re: How FPGAs work, and why people will buy them (2013)

#46

Post by aseipp »

snaky wrote: post #33
aseipp wrote: post #31

Earlier quoted context omitted.

Yes, they can do traditional cryptography pretty well (depending on the algorithm, of course.) AES-128 in an FPGA can encrypt a full 16-byte block every clock cycle when done right. With 100Mhz clock that's about 2.3Gbp/s, well within SATA 3 transfer speeds. You can achieve that with a last-last-gen FPGA that will cost you a couple bucks out of pocket, and it will use a fraction of the power/thermal footprint of any…

Or maybe, if you're going to do ubiquitous encryption for something like your SATA link at scale, with a lot of units being sold, it would be nice to only update the FPGA firmware when the exploit will be found in the implementation of your crypto.

But no hardware engineer would think of it that way in such a hypothetical product scenario, if they were designing it. Because:

- If many units are being sold, BOM choices matter. People optimize part choices down to fractions of a penny on individual units when scale is large; ASICs and FPGAs are differences in dollars, it's a completely different order of magnitude. Power usage is similarly important for the same reasons. Cost is king, and nobody will buy/integrate your 20x more expensive SATA adapter when another alternative exists that does the same job, cheaper, faster, with lower power. So what about all that alleged 'security' advantage when nobody uses your chip at all?

- There is no indication cryptographic agility is actually advantageous for any given design, it can only be assessed in the context of a threat. It may in fact be a detriment due to exposing further attack surface (e.g. you now need a secure update mechanism). This is important because the design phase is absolutely critical and takes substantial amount of the overall development/market time -- so you don't introduce extra complexity if you don't have reason to believe you need it. (And it's also why you just tend to buy many components from other vendors, because paying a bill to them is cheaper than paying your engineers to recreate everything while assuming they won't fuck up. I'd guess that very few actual FPGA/RTL engineers actually implement AES cores outside of university, as opposed to just reusing an existing one...)

Ultimately all of this comes down to your design requirements for the product, but flexibility can come with costs and in terms of money it definitely is not free.

Re: How FPGAs work, and why people will buy them (2013)

#47

Post by dmitrygr »

Cyph0n wrote: post #17
RandomInteger4 wrote: post #12

Earlier quoted context omitted.

Can you elaborate?

IEEE tracks a vast number of open standards and specifications (e.g., Ethernet, WiFi, Bluetooth). I guess the comment was pointing out that there is a degree of openness in EE.

   > IEEE tracks a vast number of open standards
And demands mega-bucks for a PDF of any of those standards

Re: How FPGAs work, and why people will buy them (2013)

#48

Post by user5994461 »

ThePadawan wrote: post #14
sfifs wrote: post #10

Earlier quoted context omitted.

Actually I recently bought a Spartan 7 based FPGA board after taking the nand2tetris course and started playing with the free version of the Vivado suite. If your complaint is principle based on the stuff being non free software, then it holds. If it's on usability - not sure it does. While lengthy, the process of compiling and getting something running on silicon didn't seem any more complicated than Grade/Maven etc…

> While lengthy, the process of compiling and getting something running on silicon didn't seem any more complicated than Grade/Maven etc all based Android Studio builds. I'm not sure many people would share your opinion that Gradle/Maven are uncomplicated. Personally, I would say they belong to the 20% most complicated build toolchains I have encountered - which would make the FPGA process still not very uncomplicate…

Maven is just right click + build to build. Or file + import to import a project.

The last time I worked with Vivado, I remember our interns couldn't manage to create a project or use an existing project after a whole week. It doesn't help that there are no tutorials from the vendor or the internet, or that projects can't be stored in source control.

Re: How FPGAs work, and why people will buy them (2013)

#49

Post by rjsw »

davemp wrote: post #20
sfifs wrote: post #10

Earlier quoted context omitted.

Actually I recently bought a Spartan 7 based FPGA board after taking the nand2tetris course and started playing with the free version of the Vivado suite. If your complaint is principle based on the stuff being non free software, then it holds. If it's on usability - not sure it does. While lengthy, the process of compiling and getting something running on silicon didn't seem any more complicated than Grade/Maven etc…

For basic implementations in ways intended by the vendor, I'm sure the supplied tools are fine. When you want to leave the sandbox and do interesting things, it's hard. I was thinking along the lines of writing your own tools that would require information about timings and chip resources/layouts. EDIT: your cpu ISA is open, but fpga layout/bit-stream is not--locking you to your vendor's innovation and ideas for how…

Lots of engineers manage to do interesting things with the vendor tools.

Re: How FPGAs work, and why people will buy them (2013)

#50

Post by davemp »

rjsw wrote: post #49
davemp wrote: post #20

Earlier quoted context omitted.

For basic implementations in ways intended by the vendor, I'm sure the supplied tools are fine. When you want to leave the sandbox and do interesting things, it's hard. I was thinking along the lines of writing your own tools that would require information about timings and chip resources/layouts. EDIT: your cpu ISA is open, but fpga layout/bit-stream is not--locking you to your vendor's innovation and ideas for how…

Lots of engineers manage to do interesting things with the vendor tools.

Mhm. I am aware.

People did interesting things chipping away with rocks as well.

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